Molten Salt-Based Solar Power Plant 478
rcastro0 writes "Hamilton Sundstrand, a division of United Technologies, announced today that it will start to commercialize a new type of solar power plant. A new company called SolarReserve will be created to provide heat-resistant pumps and other equipment, as well as the expertise in handling and storing salt that has been heated to more than 1,050 degrees Fahrenheit. According to venture capitalist Vinod Khosla 'Three percent of the land area of Morocco could support all of the electricity for Western Europe.' Molten Salt storage is already used in Nevada's Solar One power plant. Is this the post-hydrocarbon world finally knocking?"
Pretty light on detail (Score:5, Informative)
SciAm article (Score:2, Informative)
http://www.sciam.com/article.cfm?id=a-solar-grand-plan [sciam.com]
Unfortunately, it will take massive investments to make this stuff really viable. Fortunately, some European governments are stepping up with real money. Unfortunately, America hasn't for about a decade.
Article reads like a business deal. (Score:5, Informative)
Still limited by Carnot efficiency (Score:4, Informative)
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Educational microcontroller kits for the digital generation. [nerdkits.com]
Re:Pretty light on detail (Score:5, Informative)
Re:I know this is somewhat OT (Score:3, Informative)
There WAS a liquid sodium reactor in the US. The seals in the cooling system seals started to fail leading to severe consequences. See Wikipeida [wikipedia.org].
Nothing new here. See Solar Two Mojave (Score:4, Informative)
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Solar two was a flat mirror array.
Search google image search with
"solar two" Mojave
http://maps.google.com/maps?f=q&hl=en&geocode=&q=yermo,+ca&ie=UTF8&ll=34.871919,-116.83416&spn=0.005915,0.010042&t=h&z=17&om=1 [google.com]
Take the link above and zoom out, just below and to the right is a Parabolic glass mirrors plant
http://en.wikipedia.org/wiki/Solar_Two [wikipedia.org]
http://www.powerfromthesun.net/Chapter10/Chapter10new.htm [powerfromthesun.net]
http://en.wikipedia.org/wiki/Image:Solar_Two_2003.jpg [wikipedia.org]
http://en.wikipedia.org/wiki/Image:Solar_Two_Heliostat.jpg [wikipedia.org]
http://theothersolar.com/?m=200702 [theothersolar.com]
http://www.commondreams.org/headlines06/1101-10.htm [commondreams.org]
http://www.global-greenhouse-warming.com/solar-central-power-towers.html [global-gre...arming.com]
http://www.ldeo.columbia.edu/edu/dees/U4735/projections/pitman/solar.elec.jpg [columbia.edu]
http://fixedreference.org/2006-Wikipedia-CD-Selection/wp/s/Solar_power.htm [fixedreference.org]
(search for "Solar two")
http://www.reia-nm.org/HTML_Docs/Solar_Thermal_Electrical.html [reia-nm.org]
http://greatgreengadgets.com/gadgets/category/solar/ [greatgreengadgets.com]
http://www.answers.com/topic/solar-thermal-energy [answers.com]
http://blogs.business2.com/greenwombat/2006/week44/index.html [business2.com]
Excellent page on many technologies - Sorry it's in Spanish.
http://g3nergy.blogspot.com/2006_11_01_archive.html [blogspot.com]
Search for "Australia to Build 154 MW Solar Energy Plant"
This one is identical in design to the one in the Mojave Dessert here.
http://ludb.clui.org/ex/i/CA4965/ [clui.org] Abandoned Solar Power Plant
Re:I know this is somewhat OT (Score:4, Informative)
Care to guess what happens when 300 C warm and radioactive water goes from 15 mega pascal to neutral pressure within a fraction of a second after a coolant pipe bursts? No matter if it is sodium or water primary coolant leaking is a Bad Thing (tm) , and sodium has the advantage that you don't have to keep it under pressure, thus reducing the chance of a leak greatly.
In addition sodium is practically non-corrosive to steal, while boric-acid spiked water at 300 C is quite agressive. Sodium also has a much better heat conductivity than water, so the reactor won't melt down if the primary cooling pumps fail ( natural convection of the coolant is enough to cool the spent fuel once the chain reaction has stopped, as it will do due to thermal expansion of the fuel rods ).
Having said this, my favourite candidate for coolant is molten-lead. Like sodium you don't have to pressurise it, it doesn't react with water or air, it won't boil even if you overheat teh ractor so much that the steel melts, and it is an excellent radiation shield against gamma-radiation. Main issue is corrosion, but 20+ years of research has produced alloys that are very stable in molten lead, so you could expect comercial plants using it within a deacde or two.
Re:Danger Will Robinson! (Score:3, Informative)
I know, I know... why ruin jokes with facts! Why, indeed - I'm an ass. That's why!
O&M Expense (Score:3, Informative)
sPh
salt - water heat exchanger: tricky (Score:5, Informative)
Anything has its chemical activity rise exponentially with temperature (the Arrhenius equation) so as things get hotter, they get more chemically aggressive. Molten glass will dissolve bricks and mortar. Molten sodium and chlorine ions are even nastier -- a sodium ion is a very small object [chemguide.co.uk], only a little larger than hydrogen -- and can diffuse into metals, weakening them and creating leaks.
Re:I know this is somewhat OT (Score:5, Informative)
Re:Still limited by Carnot efficiency (Score:3, Informative)
Re:Pretty light on detail (Score:5, Informative)
Heat engines also require a big temperature gradient to do work at high efficiency, which makes using steam directly a harder proposal. Molten salt is well understood in used as a coolant in some types of nuclear reactors, and it works well for this purpose, and that's why it's used.
Re:Nuclear's the future. (Score:2, Informative)
source [infoworld.com]
The future is here, and it isn't nuclear.
Several liquid metal cooled reactors, actually (Score:3, Informative)
Re:A few notes and questions (Score:5, Informative)
2. It'd be mighty expensive but you could just mix it back with the non-uranium rock you dug out and put it back where you found it... A lot of that waste also isn't waste, it's fissionable material that politically isn't used (because doing so gives you plutonium easily used in weapons).
3. In 20 years we'd run out if we just used uranium in nuke plants for all our electricity. Again allow breeding to plutonium and it turns into 2000 years...
4. The top 5 known recoverable uranium holders are: Australia, Khazakhstan, Canada, USA, South Africa - they make up about 2/3rds of the total. From a Western world perspective, that's a much nicer set then the oil top 5: Saudi Arabia, Canada, Iran, Iraq, Kuwait...
Re:Still limited by Carnot efficiency (Score:5, Informative)
As for the necessity of high efficiency, it's not neccessary. Even if just a small fraction of the world's urban area was paved with inefficient solar cells, it'd still power the world. I don't care to repeat this calculation yet again (I do it about once a month it seems), but look up China's total urban area (just China's) and do the math with 10% efficient cells (less than NanoSolar's) at, say, 20% coverage and an average 100W/m^2, then compare that to the entire world's electricity demand.
As for what potential efficiency we're capable of, it's actually looking up. But not for CIGS -- for more conventional semiconductor cells, which aren't likely to be cheap enough to panel the world. We're up to a staggering 42.8% now (Honsberg and Barnett) -- and the record keeps growing at a rather surprising clip. And there's more potential for that number to keep growing up to 60-70% or so. There are three technologies pushing this -- the ability to get multiple electrons out of a single photon, the use of integrated beam splitters so that different parts of the cell can be optmized to specific parts of the solar spectrum, and the use of phosphor coatings that can be excited to release photons in a desired energy range. These technologies may not end up running our grid, but they'll be running our satellites, our malibu lights, our self-illuminated highway signs, and so forth.
Back to the initial topic: Just to drive home the point as to how much photovoltaic prices have been dropping, let's put in some historical price points (in non-inflation-adjusted dollars):
1956: Bell solar cell: $300/W .
Early 1970s: Bergman's improvements lowers the price from then $100/W to $20/W
Specifically [unu.edu] (in 1994 dollars):
1976: ~$51
1977: ~$38
1978: ~$27
1979: ~$21
1980: ~$18
1981: ~$15
1982: ~$14
1983: ~$11
1984: ~$11
1985: ~$10
1986: ~$9
1987: ~$8
1988: ~$8
1989: ~$8
1990: ~$8
1991: ~$7
1992: ~$7
1993: ~$6
1994: ~$6
In non-inflation-adjusted dollars, solar prices were at a minimum in the early '00s (~4$/W, if I recall correctly), and rose up until this summer due to supply shortages, when they started to go down again. And with the CIGS companies, the prices can be expected to go down a lot over the next several years. Anyways, I really don't see how anyone can look at the numbers and act like solar hasn't been advancing by leaps and bounds since it was first turned from a laboratory curiosity into a commercial product in the '50s.
Re:salt - water heat exchanger: tricky (Score:3, Informative)
It's not a bad idea if they have a good insulated container for the molten salt. It introduces a lot of waste because of the cumulative inefficiency of heat transfer between the different systems, but it allows a system based on this to provide more reliable energy -- energy that's closer to being on-demand, rather than just when the sun is shining strongly enough.
Re:Nuclear's the future. (Score:5, Informative)
Much of the argument against solar is one of economics, but a company called Nanosolar has recently produced solar panels making energy more cheaply than coal. [grist.org] "Current Technology" is a moving target.
Re:Nuclear is not the future.. (Score:5, Informative)
Um, no. You only need to do that if you're planning on building bombs. (And anyway, gas centrifuges don't heat the uranium to a gas but chemically convert it to uranium hexafluoride before centrifuging.)
There are plenty of reactor designs that run on unenriched uranium, including most of the nuclear power plants in Canada (CANDU) and places to where Canada has sold reactors.
Re:Nuclear is not the future.. (Score:3, Informative)
Oh, and actually it's the lighter isotope (235 vs 238) that's the one of interest.
Re:Pretty light on detail (Score:4, Informative)
The molten salt is there because it's pumpable, so that it can quickly gather up a bunch of energy from the reflectors, and just as quickly dump it through conduction when the heat is used to make steam. Water is king, in terms of storing heat, unfortunately it turns to gas at a relatively low temperature.
However in cases like the Nevada Solar One power plant, it's oil that is circulated through tubes and is heated. Then the heated oil goes through a heat exchanger where the heat is transfered to water which spins the turbines. Only if the heat can't be used right away will the heat be transfered to the salt, which stores the heat for later use.
FalconRe:Pretty light on detail (Score:5, Informative)
Re:A few notes and questions (Score:3, Informative)
Wow, there are still people out there asking this question? It's really, really simple. There are three ways to charge.
1) Slow charge overnight. Anyone can do this without any specialized hardware.
2) Fast charge at gas station. Truck stops already have a lot of power going to them, as do many gas stations, and few would hestitate to upgrade their wiring if it adds another revenue stream.
3) Fast charge anywhere using a fast charger. The same batteries used in your vehicle can charge your vehicle. They slow charge from the wall, and when you plug in, they charge your vehicle. While it's an extra purchase cost, it also provides further advantages: A) automatic grid power load balancing (a favorite of power companies), and B) home backup power
Even if the battery technology was here today, the power distribution infrastructure isn't, and isn't on its way either.
Yes it is, and yes it is (and why don't people look this up first?) Let's do the math: the average car goes something around 40 miles a day. EVs are typically 120-200Wh/mi, so that's 4.8-8kWh/day. Let's go with the high end, 8. That's 240kWh a month. At 10 cents per kilowatt hour, that's $24 a month. Compare that to your monthly power bill, and notice something? Your existing power usage almost certainly dwarfs that which would be used by an EV, especially in the summer (midday during the summer most accurately reflects our generation baseline). Even if you merely use 20% less power at night during the day (as opposed to the more typical usage of several times less power at night than during the day), that right there is enough to charge your vehicle.
Even if this *wasn't* the case, it's much easier to build power generation and transmission infrastructure than it is to replace aging oil infrastructure and develop new fields, so it's a rather dumb argument to make to begin with.
You didn't even discuss range, yet claimed that it will remain insufficient without any evidence to counter what I wrote. No surprise there.
Re:sun renewable? (Score:3, Informative)
There is no *real* renewable energy, laws of ethropy make that an impossible thing. A perpetual motion machine is impossible (as far as we know). That's why "renewable energy" means something else, basically an energy source that is not permanently depleted by us humans using it.
It's a bit of a definition issue really. For example there is some controversy wether peat should be considered renewable or non-renewable, as it takes hundreds or thousands of years for a peat swamp to accumulate. Still, if you count all the peat accumulated over a year, you can harvest an awful lot of it without taking more than is accumulated back.
So the teacher was right, but apparently she was unable to explain or understand the conecpt properly, which isn't very good either.
Re:Pretty light on detail (Score:5, Informative)
Think about it -- these plants have to store heat; heat is proportional to mass, which scales as cube of diameter. Meanwhile, they lose heat at a rate that is proportional to surface area, which scales as the square of diameter. You need only the most basic math skills to see that this results in VASTLY better efficiency at larger sizes.
But, no, I'm sure you're much smarter than... you know... the actual engineers and physicists who designed this plant. Or the people who built any of the nuclear plants that pump liquid salt to transfer heat. Those silly people, they've probably never even HEARD of using oil to store heat!
Solar panels and cells are expensive to produce, and the process uses tremendous amounts of energy. After all, it requires producing perfectly pure silicon, not a trivial task. And a huge amount of waste is produced in the process.
That's not to dismiss solar cells -- but we need to explore every avenue. And at the large scales where power plants become commercially viable, heat engines rule. Coal and gas-fired reactors, as well as nuclear plants, they're all just big heat engines. Heat engines have over two centuries of engineering research and development behind them. And Semiconductors just can't be produced in large enough quantities cheaply enough (yet).
Re:sun renewable? (Score:3, Informative)
Synthesized oil or coal are not energy sources, they are ways to store energy. Energy for the synthetication must come from some actual energy source. Fossil oil and coal are energy sources for humans, but they are non-renewable because more of them will not appear from anywhere (not in human time-scales anyway), and they get less and less as we use them. And even though the energy for the fossil fuels came from the Sun, we are harvesting it from the fossil fuel, so the fossil fuel is considered to be the energy source for us (and same with wind power etc), even if it is originally the Sun's energy (which is originally energy from the Big Bang, which got it's energy from nobody-really-knows-where).
Also, plants grown with other than sun light aren't energy sources. Then the energy source is whatever is used to power the artifical lights for growing them.
Fusion energy will not be renewable either, because the more we use it, the less of it there is left. There's just so much of it (except usable reserves of the "ultimate fusion fuel", Helium-3, may be limited within our solar system) that we won't run out.
Sun's enegy output is the only known renewable origin of energy in our solar system, because it doesn't matter if we use it or not, there won't be any more or any less of it left, no matter how much solar energy we collect. Also, any energy source that uses the Sun's energy and grows/accumulates back in human time-scales, is considered renewable, such as wind or naturally (without non-renewable fossil fuel based fertilizers) grown biomass. They "come back" quite fast, and if we use it at most at that rate, we will never run out.
Re:Nuclear is not the future.. (Score:1, Informative)
Some people think that wind has no place on the grid since it will fail to provide any power in the statistically impossible scenario where the wind isn't blowing anywhere in for example all of Europe. But that's of course a crackpot argument. If you build wind generators all over a continent you will have power all the time. Not getting enough power? Just build more generators, and on windy days you use the excess power to make hydrogen for cars and other off-grid energy using devices. While the variations in power output of solar/wind/tidal plants is a distinctly non-trivial problem, the pieces of the puzzle are known and the problem is certainly solvable.
Correcting misunderstandings in parent post (Score:3, Informative)
The difference in consumer voltage between Europe, Japan and the US is a non-issue - we transport electricity at a much higher voltage, and then transform it down close to the point of use. The same isn't quite true for frequency - it is synced at 50/60Hz in the grid - but there are production facilities in operation that produce it at a different frequency and convert it to the grid frequency using a frequency changer [wikipedia.org]. You can read more about in Wikipedia's utility frequency [wikipedia.org] article.
The main problem with interconnecting the continents is the power loss associated with long distance transmission. As far as I understand, this makes interconnection impractical at the moment - local storage (as in the reservoirs described above) being more economical. Superconductors may some day change this.
Eivind.
Re:Nuclear is not the future.. (Score:3, Informative)
That article doesn't support what you claim.
It's not the reprocessing that's the problem, it's the lack of economical breeders. More research into things like the IFR is most definitely called for.